Intro to Anatomy and Physiology — Study Notes (OpenStax slides)

Course Logistics and Resources

  • Instructor: Dr. Mark MacDougall

    • Email: macdougallm@brandonu.ca

    • Office: 3-11 in Brodie

  • Course Breakdown (Weights):

    • Term test 1: $15\%$ on Oct 6

    • Term test 2: $15\%$ on Nov 7

    • Moodle Quizzes: spread throughout course; $10\%$; announced in lecture and on Moodle

    • Final Exam: $30\%$; date TBA

    • Lab Component: weekly; $30\%$

  • Resources:

    • Lecture notes and lab information posted on Moodle

    • Moodle enrolment password: histology

  • Textbook: OpenStax Anatomy and Physiology, 2nd edition

  • Course Learning Objectives (Overview):
    1) The types of cells and tissues that make up the human body
    2) The various organs and organ systems of your body
    3) How those cells, tissues, and organ systems function

Textbook and Learning Goals

  • Textbook: OpenStax Anatomy and Physiology, 2nd edition

  • Focus Areas: cellular/tissue composition; organ systems; functional integration

What is Anatomy?

  • Definition: Anatomy is the study of the body’s many structures

  • Etymology: The word anatomy comes from a Greek root meaning to cut apart

  • Visuals Referenced: Encyclopedia Britannica image (for definition and origin)

History of Human Anatomy

  • Early Evidence and Practices:

    • Trepanation (hole drilled into skull to relieve pressure) found in neolithic skulls; viewed as primitive emergency surgery

  • Written Records and Early Terms:

    • First written anatomical terms/observations in Egyptian medical writings (oldest around $1600\,\text{BCE}$; likely based on even older sources)

  • Greek Contributions:

    • Greek physicians like Hippocrates advanced comparative anatomy; Hippocratic Oath bears his name

  • Renaissance to Modern Anatomy:

    • Wound Man of 1491 as early anatomical compilation

    • Leonardo da Vinci’s drawings are famous; Andreas Vesalius (1514–1564) credited as founder of modern anatomy

  • Dissection and Microscopes:

    • Renaissance allowed corpse dissection for study; grave robbing common before this

    • 17th century: invention of the microscope facilitated histology and cell descriptions

Gross vs. Microscopic Anatomy

  • Gross Anatomy: study of structures visible to the naked eye

  • Microscopic Anatomy: study of tissues/cells requiring microscopes

    • Subdisciplines: Cytology (cell study) and Histology (tissues)

Regional vs. Systemic Anatomy

  • Regional Anatomy: study of all structures in a specific body region (muscles, nerves, vessels, etc. within that region)

  • Systemic Anatomy: study of parts that make up a discrete body system (e.g., cardiovascular system as a whole)

  • Example/Professional Focus: some doctors specialize by region (e.g., gastroenterologists focus on the GI region)

Levels of Organization (Hierarchy of Life)

  • Investigation Approach: smaller parts assemble into larger structures

  • Hierarchical Order (from smaller to larger):

    • Cells → Tissues → Organs → Organ Systems → Organism

    • Organelles within cells; cells are eukaryotic and contain various organelles

  • Emphasis: understanding how structures at one level contribute to functions at higher levels

Cells, Tissues, and Organs

  • All living structures are made up of cells; cells perform all life functions

  • Cells are often specialized for specific functions

  • Cells organize into tissues (mass of similar cells performing a common function)

  • Stem Cells: unspecialized but can give rise to specialized cells/tissues

  • An Organ: anatomically distinct body part composed of two or more tissues; most organs have a primary function and often secondary functions

  • Example: Skeletal muscles attach to skeletal elements and move them; under certain conditions they generate heat (shivering) as a secondary function

What is Physiology?

  • Physiology vs. Anatomy:

    • Anatomy: structure; Physiology: function

  • Physiology Definition: the scientific study of the chemistry and physics of body structures and how they work together to support life

Functions of Human Life (Key Concepts of Physiology)

  • Five broad ideas define life processes (summarized into six key concepts):
    1) Organization
    2) Metabolism
    3) Responsiveness
    4) Movement
    5) Development and growth
    6) Reproduction

Functions of Human Life: Organization

  • Life is highly organized from cellular to organismal levels

  • Example: cell membranes maintain intracellular vs. extracellular environments

  • Visual Reference: OpenStax diagram of organization

Functions of Human Life: Metabolism

  • Organismal energy management and biosynthesis

  • Two Main Reaction Types:

    • Anabolism: smaller to larger, more complex molecules assembled using energy

    • Catabolism: larger molecules broken down into smaller units, releasing energy

  • Metabolism = sum of all anabolic and catabolic reactions; both are continuous

  • Visual References: Nature.com diagrams for anabolism/catabolism

Functions of Human Life: Responsiveness

  • Ability to adjust to internal and external changes

  • Examples: sweating (thermoregulation), vasodilation in skin to lower body temperature

Functions of Human Life: Movement

  • Movement includes joint actions, organ movements, and even cellular movements

  • Encompasses both voluntary and involuntary movements

Functions of Human Life: Development and Growth

  • Development includes differentiation: unspecialized cells become specialized

  • Growth and tissue repair are also components of development

  • Includes changes across the lifespan

Functions of Human Life: Reproduction

  • Formation of a new organism from parents; humans reproduce via male and female systems

Requirements for Human Life (Four Major Requirements)

  • Oxygen ($O_2$)

  • Nutrients

  • Narrow range of temperature

  • Narrow range of pressure

Requirements for Human Life: Oxygen

  • Atmosphere $\sim 20\%\ O_2$

  • $O_2$ is essential for ATP production; critical in metabolism

  • Brain cells are highly sensitive due to high/steady ATP demand

  • Brain damage likely within $5\,\text{min}$ without oxygen; death likely within $10\,\text{min}$

Requirements for Human Life: Nutrients

  • Nutrients: substances in foods/beverages essential for survival

  • Three Basic Classes:

    • Water

    • Energy-yielding and body-building nutrients

    • Micronutrients (vitamins and minerals)

  • Most important nutrient: water; survival without water can be only a few days

  • Energy-yielding nutrients: carbohydrates and lipids

  • Proteins provide amino acids for body structure and enzymes

  • Micronutrients participate in many reactions (e.g., nerve impulses); calcium contributes to body structure

Requirements for Human Life: Narrow Range of Temperature

  • Chemical reactions operate within a narrow temperature window around $37^{\u00b0}\mathrm{C}$

  • If temperature deviates too far, enzymes lose structure and function; metabolism fails

  • Body responses to temp changes include sweating (heat) and shivering (cold)

  • Temperature Reference: $37^{\u00b0}C$

Requirements for Human Life: Narrow Range of Pressure

  • Atmospheric pressure maintains gas exchange and bodily gas solubility

  • Breathing depends on precise pressure; altitude sickness occurs due to decreased pressure at high altitude

Homeostasis: The Body’s Internal Balance

  • Definition: steady state of body systems maintained by continuous monitoring of internal conditions

  • Set Point: the physiological value around which normal range fluctuates (e.g., body temperature $\sim 37^{\u00b0}C$)

  • Normal Range: restricted range around the set point that supports health

  • Control centers monitor deviations and coordinate responses

Homeostasis: Negative Feedback

  • Mechanism that reverses a deviation from the set point

  • Three Components of a Negative Feedback Loop:

    • Sensor (receptor): monitors a value

    • Control Center: compares value to normal range

    • Effector: produces a response to restore normal value

  • Objective: keep parameters within normal range

Homeostasis: Positive Feedback

  • Positive feedback intensifies a change rather than reversing it; is normally self-limiting when there is a definite end point

  • Examples: childbirth; response to blood loss

  • Note: positive feedback is not typically a daily regulator, but functional in specific scenarios

Anatomical Terminology and Positioning

  • Anatomical Terminology: terms derived from Latin/Greek roots; roots indicate organ/tissue/condition; prefixes/suffixes describe the root

  • Example: hypertrophic means enlarged; from hyper- (high/over) + trophia (nourishment)

  • Anatomical Position: standard reference position for describing anatomy

    • Feet shoulder-width apart

    • Arms at sides with palms facing forward (supinated)

  • Purpose: to minimize confusion in communication regardless of body orientation

Directional Terms and Body Landmarks

  • Anterior vs. Posterior: front and back of body or body part

  • Dorsal vs. Ventral: back and belly (for trunk/main body)

  • Superior vs. Inferior: top vs. bottom

  • Cranial vs. Caudal: toward the head vs. toward the tail

  • Medial vs. Lateral: relative to the midline

  • Proximal vs. Distal: closer to vs. farther from the trunk/base of a limb

  • Superficial vs. Deep: near surface vs. away from surface

  • Example: clavicle has a medial end (toward sternum) and a lateral end (toward scapula)

Planes and Body Planes

  • Sagittal Plane: runs through the midline; parasagittal planes run parallel to it

  • Frontal (Coronal) Planes: vertical planes at right angles to the sagittal plane; divide into anterior vs. posterior parts

  • Transverse (Axial) Planes: perpendicular to both sagittal and frontal; divide into superior vs. inferior parts

  • Planes are conceptual and aid in describing locations within the body

Body Cavities and Membranes

  • Dorsal (Posterior) Cavity: houses brain and spinal cord; subdivided into cranial and vertebral (spinal) cavities

  • Ventral (Anterior) Cavity: subdivided into thoracic (superior) and abdominopelvic (inferior)

  • Membranes line cavities to support and protect enclosed organs; membranes allow organ movement/size changes without organ distortion

  • CSF (Cerebrospinal Fluid): bathes brain and spinal cord; produced by the brain; cushions these structures

  • Lumbar Puncture (Spinal Tap): sampling CSF to test for conditions like meningitis

  • Thoracic Cavity Contents: lungs and heart

  • Abdominopelvic Cavity: contains digestive and reproductive organs

  • Subdivisions of Abdominopelvic Cavity:

    • Nine-region scheme (epi, hypo prefixes; gastric, lumbar, iliac, chondro- suffixes)

    • Four-quadrant scheme

Medical Imaging: A Historical and Practical Perspective

  • Historical Milestones:

    • Early reliance on gross anatomy (wounds, suturing, amputations, skull procedures)

    • Invention of the microscope (Leeuwenhoek) enabled cell theory and histology

    • X-rays discovered by Wilhelm Röntgen in the late 19th century; popularized by imaging of hands in 1895

  • X-rays:

    • High-frequency radiation that penetrates varying densities; bones reveal well; soft tissues less visible

    • Lead blocks exposure; risk of DNA damage and cancer with excessive exposure

    • Relatively inexpensive; two-dimensional images from a single angle

    • Limitations: lack of depth and multiple exposures

  • CT (Computed Tomography):

    • $360^{\u00b0}$ rotation around the subject to create a series of X-ray images

    • Provides 2D slices of the scanned area; excellent for soft tissues

    • Higher radiation dose than plain X-ray; more precise 3D representations

    • Especially useful for brain and muscle visualization

  • MRI (Magnetic Resonance Imaging):

    • Uses magnetic fields and radio waves to elicit signals from tissues

    • Tissue contrast differences reveal abnormalities; not suitable for patients with ferromagnetic implants

    • Noninvasive; no ionizing radiation

  • PET (Positron Emission Tomography):

    • Uses radiopharmaceuticals to image physiological activity (e.g., metabolism, blood flow)

    • Broad diagnostic applications (heart, cancer spread, brain, bone, thyroid)

  • Ultrasonography:

    • High-frequency sound waves produce real-time images

    • Safe and least invasive; useful for fetal development, heart function, blood flow

    • Limitations: operator dependence and poor penetration of bone/gases

  • Practical Takeaway: each modality has specific advantages, limitations, and safety considerations; choice depends on tissue type, required information, and patient factors

Intro to Anatomy: Summary and Next Readings

  • Core Questions:
    1) What are anatomy and physiology? How can they be studied?
    2) What are the levels of organization in the body?
    3) What are the functions and life-sustaining requirements of humans?
    4) What are key anatomical terminologies and how are planes, cavities, and directions defined?
    5) What imaging techniques are available for studying anatomy?

  • Readings for Next Week: The Chemical Level of Organization; The Cell and its Components (OpenStax) – Chapters 2 and 3

  • Reference: OpenStax Human Anatomy and Physiology textbook, chapters 2 and 3

Notes on Formulas, Numbers, and Units (LaTeX format)

  • Oxygen content of air: $O_2\ \text{concentration} \approx 20\%$

  • Normal body temperature: $T \approx 37^{\circ}\mathrm{C}$

  • Critical time without oxygen: $t{\text{damage}} \approx 5\,\text{min}$; $t{\text{death}} \approx 10\,\text{min}$

  • Nutrient classifications: water; energy-yielding nutrients (carbohydrates, lipids); body-building nutrients (proteins); micronutrients (vitamins/minerals)

  • Planes and regions: sagittal, parasagittal, frontal (coronal), transverse; **nine-region and four-quadrant